Hinge means for foldable frame structures for longitudinal relative movement



Feb. 3, 1970 E. J. TASSET ET L v HINGE MEANS FOR FOLDABLE FRAME STRUCTURES FOR LONGITUDINAL RELATIVE MOVEMENT Filed 001'.- 9. 1967 2 Sheets-Sheet 1 F/GZ R G 0mm TNS. mm VH w mcJr .m T R B T N 0 A5 T Mm WV ME Feb. 3, 1970 .T SET ET AL 3,493,246

E. J HINGE MEANS FOR F DABLE FRAME STRUCTURES FOR LONGITUDINAL RELATIVE MOVEMENT Filed Oct. 9, 1967 2 Sheets-Sheet 2 'llL'giiiiis i i iii 'iii him? 4s\\ J 45 I REF F/G' 6 102 lbe 97 H I-NVENTOR.

ATTORNEYS I MICHAEL c. uonmme 715- i BY EVERETT Zyssm United States Patent HINGE MEANS FOR FOLDABLE FRAME STRUCTURES FOR LONGITUDINAL RELA- TIVE MOVEMENT Everett J. Tasset and Michael C. Hornung, Spearville,

Kans., assignors to American Products, Inc., Spearville, Kans.

Filed Oct. 9, 1967, Ser. No. 673,784 lint. Cl. B62d 53/00 US. Cl. 280-411 8 Claims ABSTRACT OF THE DISCLOSURE A hinge for longitudinal relative movement of a folding link means of a foldable frame means is provided wherein the foldable frame means has a frame structure and a sectional support beam having a central section and opposed end sections pivotally connected thereto and said central section connected to said frame structure and transversely extends therefrom. The hinge is so designed that it enables the folding link means to rise up and over the frame structure without the necessity of guiding means when the structure is folded. The hinge is connected to a bracket means mounted on the opposed end sections of a sectional support beam rotatable about a substantially horizontal axis through the bracket. The hinge is further provided with an inclined axis relative to the horizontal axis through the bracket means which is pivotally connected to the rearwardly extending end portion of the folding link means thus allowing link means to rise up and over the frame structure and then drop back down on the frame structure for additional support.

This invention relates to implements. In one aspect it relates to a foldable frame structure for farm implements. In another aspect it relates to a hinge for longitudinal relative movement of a folding link means. In another aspect it relates to a hinge for longitudinal relative movement of a folding link means of a foldable frame structure which enables the folding link means to rise up and over the frame structure without the necessity of guiding means when the structure is folded.

In another aspect it relates to a hinge for longitudinal movement of a folding link means of a foldable frame structure which enables the folding link means to rise up and over the frame structure without the necessity of guiding means when the structure is folded and subsequently dropped down on the frame structure for additional support.

Farm implements are known in the prior art which operate to cultivate or break up the earth surface. Because of the need to work the surface in a minimum period of time it is desirable to join a number of ground working implements together in order to work a large swath of ground in a single path. However, in doing so the joined implements have created problems when moving the implement from one field to another and through gates and the like. Foldable frame structures are also known. However, most of the foldable frame structures of the prior art suffer from the disadvantage that when the prior art devices are in the folded position the frame sections are not maintained horizontal. This has created serious problems where an implement such as a grain drill has been'mounted 0n the frame structure in that when the frame structure is folded the grain must be emptied or else the grain will be caused to spill. Due to the desire to maintain the frame section in a horizontal position both the extended working position and in the folding position problems have arisen in that the folding link means of the foldable frame structure are not capable 3,493,246 Patented Feb. 3, 1970 of rising up and over the frame structure without the need for auxiliary guiding equipment. Further, when the folding link means are guided over the frame structure by the guiding means the stress and strain created on the folding link conduit means causes a warping of the folding conduit means and thus frequent repairs must be made.

According to the present invention, we have now provided a hinge for longitudinal relative movement of the folding link means of a foldable frame means which enables the folding link meansto rise up and over the frame section of the foldable frame means and then drop into position and be supported by the frame means without the need for auxiliary guiding means.

Further, according to the invention, we have found, that by employing a hinge means pivotally connected to a bracket means mounted on a sectional support beam which is connected to the frame structure and transversely extends therefrom which is rotatable about a substantially horizontal axis through the bracket means and the hinge is further provided with an inclined axis relative to the horizontal axis through the bracket means and spaced therefrom that the bracket and hinge means are constructed and cooperatively connected so that upon the frame means being folded the folding link means rises up and over the frame structure without auxiliary guiding means.

Further, according to the invention, we have now found that the inclined axis of the hinge means to the horizontal axis of the bracket varies depending upon the length of the sectional support beam and is generally within the range of five to eleven degrees.

Further, according to the invention, we have found that the inclined axis of the hinge means relative to the horizontal axis of the bracket means for sectional support beams having a length within the range of about 24 to 34 feet is about seven degrees.

Further according to the invention we have found that the inclined axis for the hinge means relative to the horizontal axis of the bracket means is about ten degrees when the length of the sectional support beam is about forty feet in length.

Further according to the invention, we have found that by pivotally connecting the rearwardly extending end portion of the folding link, means to the hinge means wherein the hinge means is provided with an inclined axis relative to the substantially horizontal axis of a bracket means mounted on the sectional support beam to which the hinge means is likewise rotatably connected the structure can be positioned in a forward. foldable position maintaining the sectional support beam, and thus the implement maintained thereon in a horizontal position, and at the same time, allowing the folding link means to rise up and over the frame structure and subsequently drop back down on the frame structure thereby providing support for the folding link means in the folded position without placing undesirable stress and strain on said folding link means.

Further according to the invention, we have found that by constiucting and cooperatively connecting a hinge of two U-shaped yoke members wherein the first yoke member is pivotally connected to a bracket means mounted on the end section of the sectional support beam and rotaable about a substantially horizontal axis through the bracket means and the second yoke member is connected to the first yoke member so thgt the second yoke member is provided with an inclined axis in the range of about 7 to 10 degrees with respect to the horizontal axis of the first yoke member and the folding link means is pivotally connected to the inclined axis of the second yoke memher that the folding link means of the foldable frame means is caused, upon folding the foldable frame means,

to rise up and over the frame structure and subsequently drop back down on the frame structure thereby providing support for the folding link means.

An object of this invention is to provide a hinge means for foldable frame structures for longitudinal movement.

Another object of this invention is to provide a hinge means for a forwardly foldable frame structure wherein the frame structure is maintained in a horizontal position in both the extended working position and the folded position.

Another object of this invention is to provide foldable frame structure having a hinge means for longitudinal movement which allows the folding link means of the foldable frame structure to be folded inwardly towards the frame structure and, at the same time, allowing said folding link means to rise up and over said frame structure without the need for auxiliary guide means.

Another object of this invention is to provide a hinge means which allows the folding link means of the foldable frame structure to rise up and over the frame structure and then drop back into place to be supported on the same structure without creating strain on the folding link means thus causing warping of the folding link means.

Another object of this invention is to provide a foldable frame structure having a hinge means for longitudinal movement of the frame structure that provides quick, easy and simple adjustments thereof.

Another object of this invention is to provide a unique hinge means for foldable frame structures for longitudinal movement which is structurally sound, economical to manufacture, and which provides for an improved foldable frame structure.

Various other objects, advantages and features of the invention will become apparent to those skilled in the art from the following discussion taken in conjunction with the accompanying drawings in which:

FIG. 1 is a fragmentary top plan view of a foldable frame structure having hinge means for foldable frame structures for longitudinal movement according to the present invention;

FIG. 2 is a side plan view showing the foldable frame structure in a folded position;

FIG. 3 is a top plan view of the foldable frame structure in a folded position showing the frame structure supporting the folding link means when the same is in a folded position;

FIG. 4 is a fragmentary enlarged elevational view of the hinge means for foldable frame structures for longitudinal movement according to the present invention;

FIG. 5 is an end plan view showing the hinge of FIG. 4 and the inclined axis of the hinge; and

FIG. 6 is an end plan view of the hinge of FIG. 4 showing another inclined axis of the hinge.

The following is a discussion and description of the preferred specific embodiments of the hinge means for foldable frame structures for longitudinal movement of this invention, such being made with reference to the drawings whereupon the same reference numerals are used to indicate the same or similar parts and/ or structure. It is to be understood that such discussion and deecription is not to unduly limit the scope of the invention. In the following description of the drawings only one element of a plurality of similar elements will be described for the sake of simplicity.

Referring now to the drawings in detail, and in particular to FIG. 1, there is shown a foldable frame structure 11 connected to a conventional farm tractor 12 or the like. Frame structure 11 is provided with a generally horizontally disposed A-shaped frame means 13, a pair of forwardly converging elongated linkage members 14 and 16, a pair of first wheel means 17, a sectional support beam 18, a pair of forwardly converging folding link conduit means 19 and 21 and a pair of second wheel means 22,

A-shaped frame means 13 is provided with tongue member 23 having an aperture 24 in its forward end portion for connecting foldable frame structure 11 to tractor 12 or any other suitable towing means. A-shaped frame means 13 is likewise provided with forwardly converging elongated members 26 and 27 secured to tongue member 23 and connected rearwardly therefrom by cross member 28 which is also connected to tongue member 23. The rearwardmost ends of elongated members 26 and 27 are pivotally connected to sectional support beam 18 by bracket means 29 thereby connecting sectional support beam 18 to A-shaped frame means 13 so that sectional su port beam 18 transversely extends therefrom. Lock means 31 is mounted intermediate of cross member 28 at a point adjacent tongue member 23 where cross member 28 and tongue member 23 are joined.

Sectional support beam 18 is provided with central section 32 having opposed end section 3.3 pivotally connected to central section 32 by hinge means 34. Central section 32 and opposed end section 33 are preferably formed of square shaped or rectangular tubing material and positioned so that opposed end section 33 can be aligned through hinge means 34 or opposed end section 33 can be forwardly folded with respect to central section 32 at hinge means 34. Opposed end section 33 of sectional support beam 18 is supported by second wheel means 22.

Second wheel means 22, only one of a pair is shown, is provided with wheel member 36 positioned at the outer end portion of opposed end section 33. Wheel member 36 is operatively connected to axial spindle 37 which is connected to and supported from arm 38 depending from bracket means 39 which in turn is secured to opposed end section 33 of sectional support beam 18 by any suitable means such as welding, bolting, and the like. Cylinder and piston means, such as hydraulic cylinder 41 is mounted on arm 38 and is operatively connected to the opposed end section 33 so that upon activation of the hydraulic cylinder 41 wheel member 36 is caused to be raised and lowered in response thereto.

Forwardly converging folding conduit link means 19 and 21 are pivotally connected at their forward extending portion to tongue member 23 and A-shaped frame means 13 by support member and hinge elements 43 and 44. Support member 42 is connected to tongue member 23 by any suitable means such as welding, bolting, and the like. Folding link conduit means 19 is connected at its rearwardmost end to opposed end section 33 of sectional support beam 18 by hinge means 46 and pin element 47. Folding link conduit means 21 is likewise secured to the other opposed end section (not shown) of sectional support beam 18 in an identical manner. Hinge means 46 will be discussed in detail hereinafter. Folding link conduit means 19 is provided with two fluid-tight conduit members 48 and 49 and folding link conduit means 21 is likewise provided with two fluid-tight conduit members. Fluid-tight conduit members 48 and 49 are pivotally connected at their adjacent ends by hinge means 51. Fluidtight members 48 and 49 of folding link conduit means 19 can be maintained in aligned position, as can the two fluid-tight conduit members of folding link means 21 (not shown), or in a folded position for transportation from one location to another as shown in FIG. 2. Plate element 52 is mounted on fluid-tight conduit member 48 of folding link conduit means 19 so that when fluid-tight conduit members 48 and 49 of folding link conduit means 19 are aligned, pin elements 53 can be inserted within plate element 52 and thus fluid-tight conduit member 49 thereby securing folding link conduit means 19 in a relatively fixed position. When it is desirable to fold frame structure 11 pin element 53 is removed from plate element 52 and thus fluid-tight conduit member 49 and folding link conduit means 19 is moved inwardly over A-shaped frame means 13 and positioned within lock means 31. Upon causing folding link conduit means 19 to be moved inwardly, opposed end section 33 of sectional support beam 18 is caused to be moved in a forward direction with respect to central section 32 of sectional support beam 18. Due to the unique design of hinge means 34, opposed end section 33 of sectional support beam 18 will be maintained in a horizontal position when in the extended position and when in the folded position.

A plurality of flexible conduit means, such as those members 54 and 56 are connected to adjacent end portions of fluid-tight conduit members 48 and 49 of folding link conduit means 19 so that the fluid-tight conduit members 48 and 49 are in fluid communication with each other.

A second plurality of flexible conduit means, such as hose members 57 and 58, are connected to the rearwardly extending end portion of folding link conduit means 19 at one end and to hydraulic cylinder 41 carried by arm 38 of second wheel means 22 at the other end thus providing fluid communication between folding link conduit means 19 and hydraulic cylinder 41. A third plurality of flexible conduit means, such as hose members 59 and 61, are connected at one end to connector means 62 and 63 of tractor 12 which in turn are connected to a fluid supply source (not shown). The other end of hose members 59 and 61 are connected to two T-coupling members, such as T-coupling member 64. As illustrated in FIG. 1, coupling T-member 64 is shown connected to hose member 59. Flexible conduits such as hose members 66 and 67 are connected to coupling T-member 59 and to the forwardly converging end portion of folding link conduit means 19 and 21, respectively, thereby providing fluid communication between the fluid supply source, folding link conduit means 19 and 21 and thus hydraulic cylinder 41 of second wheel means 22. Flexible conduits, such as hose members 68 and 69 are connected to a second coupling T-member (not shown) is at one end and to the forwardly converging end portions of folding link conduit means 19 and 21, respectively at the other end thereby providing fluid communication between the fluid supply source, folding link conduit means 19 and 21 and thus hydraulic cylinder 41 of second wheel means 22.

Referring now to FIG. 2, in conjunction with FIG. 1, forwardly converging elongated linkage member 16 is pivotally connected at its forwardmost end portion to linkage member 71 by any suitable means, such as pin element 72. Linkage member 71 is then connected to couple member 73 by pin element 74 to allow linkage member 71 to be moved in a back and forth direction. Coupling member 73 is connected to tongue member 23 of A-shaped frame means 13 by any suitable means such as welding. The rearwardly extending end portion of elongated linkage member 16 is pivotally connected to connecting means 76 by pin element 77. Connecting means 76 is provided with leg members 78 and 79. Leg member 78 is pivotally connected to axial spindle 8-1 of first wheel means 17 and leg member 79 is pivotally connected to bracket means 82 which in turn is mounted on bracket means 29 which is connected to central section 32 of sectional support beam 18. As can clearly be seen elongated linkage member 16, and thus elongated linkage member 14 (not shown) are maintained above and in spaced relationship with A-shaped frame means 13 by linkage member 71, coupling member 73 and connecting means 76.

A second cylinder and piston means, such as pneumatic cylinder or hydraulic cylinder 83, is provided with a shaft member 84 which is pivotally connected at one end to linkage member 71 by pin element 86. Hydraulic cylinder 83 is then mounted on tongue .member 23 of A-shaped frame means 13 by any suitable means such as bracket and pin means 87 and the like. A plurality of fluid conducting means, such as hose members 88 and 89 are operatively connected to hydraulic cylinder 83 at one end and to connector means 91 and 92 mounted on tractor 12 at the other end. Connector means 91 and 92 are in fluid communication with the fluid source (not shown) carried by the tractor. As can clearly be seen in FIG. 2, opposed end section '93 of sectional support beam 18 is positioned in a forwardly extended folded position with respect to central section 32 of sectional support beam 18. Wheel member 36 of second whee-l means 22 is illustrated in a retracted position and, the extended position is illustrated by the dashed lines, and first wheel means 17 is shown having wheel member 94 in an extended position so that the entire frame structure is carried thereon. As can clearly be seen when wheel member 36 is in the retracted position due to the operation of hydraulic cylinder 41 carried by arm 38 of second wheel means 22 the folded structure can be transported from one location to another without damage to second wheel means 22.

Referring now to FIG. 3, foldable frame structure 11 is depicted in the folded position to facilitate transportation of the same from one location to another and through restricted areas such as gates and the like. In order to describe foldable frame structure 11 as shown in the folded position, the operative steps necessary to position foldable frame structure 11 in an extended working position, as shown in FIG. 1, from a folded position as shown in FIG. 3, will be discussed. Foldable frame structure 11 is connected to tractor 12 and is transported in the folded position to the field to be worked. Wheel members 36 of second wheel means 22 are in a retracted position and wheel members 94 of first wheel means 17 are in an extended position during transportation of the implement from one location to another. An important advantage of the invention can readily be seen by referring to FIG. 2 in conjunction with FIG. 3, namely, the forwardly foldable opposed end sections 33 and 93 of sectional support beam 18 remain in a horizontal position when in the folded position. Still another important advantage of the present invention can clearly be seen wherein folding link conduit means 19 is shown at the breakaway portion being supported by elongated member 26 of A-shaped frame means 13 while positioned within lock means 31 thereby relieving stress and strain on folding link conduit means 19. In order to more fully describe the invention the operative steps required to fold the foldable frame structure 11 to the position as shown in FIG. 3 from the extended working position as shown in FIG. 1 will be discussed. When it is desirable to position the foldable frame structure 11 in a forwardly extended folding position, hydraulic cylinder 83 is acti vated thus causing shaft 84 and elongated linkage member 16 to be moved in a forward direction thus lowering wheel members '94 first wheel means 17 and raising sectional support beam 18 thus raising the implement connected thereto. A second selector switch or lever, carried by tractor 12 is then employed to activate the hydraulic cylinder 41 of second wheel means 22 thus causing second wheel means 22 to be operated to raise wheel members 36. Folding conduit means 19 and 21 are then caused to be moved in an inward direction over A-shaped frame means 13 and into position within lock means 31. By the lowering of first wheel means 17 and the raising of second wheel means 22, second wheel means 22 are positioned so that foldable frame structure and thus the implement carried thereon can readily be moved from one location to another without wheel members 36 second wheel means 22 contacting the ground and thus causing damage thereto. As folding link conduit means 19 and 21 are caused to be moved inwardly the unique design of hinge means 46 which connects the rearward extending end portion of folding link conduit means 19 and 21 to opposed end section 33 and 93, respectively of sectional support beam 18 allows folding link conduit means 19 and 21 to rise up and over A-shaped frame means 13 and drop into contact with lock means 31 without the need of auxiliary guiding means or without placing undesirable stress and strain on folding link conduit means 19 and 21. As can clearly be seen in FIG. 3, folding link conduit means 19 when positioned within lock means 31 is suported by A-shaped frame means 13 thereby lessening the stress on folding link conduit means 19 and thus opposed end section 33 of sectional support beam 18. Likewise, folding link conduit means 21 is supported in the same vmanner.

Referring now to FIG. 4, hinge means 46 is illustrated pivotally connected to bracket 96 by pin element 47. Bracket 96 is mounted to opposed end section 33 of sectional support beam 18 by any suitable means such as welding, bolting, and the like. Hinge means 46 is provided with a first yoke member 97 having two parallel leg members 98 and 99 maintained in a spaced relationship with each other by base member 101 connected to one end of each of leg members 98 and 99. Leg members 98 and 99 are provided with axially aligned openings at their end furtherest removed from base member 101 so that pin element 47 can be positioned within bracket 96 and first yoke member 97 thereby pivotally connecting the same therein. As can readily be seen, first yoke member 97 is of U-shaped and is pivotally connected to bracket 96 and rotatable about a substantially horizontal axis through bracket 96.

A second yoke member 102 having tWo parallel leg members 103 and 104 maintained in a spaced relationship with each other by base member 106. Second yoke member 102 has its base member 106 mounted on the exterior portion of base member 101 of first yoke member 97 so that second yoke member 102 is provided with an inclined axis relative to the substantially horizontal axis through first yoke member 97 and bracket 96. Second yoke member 102 is also illustrated as a U-shaped member.

Pivoting bracket 107 is mounted on the rearwardly extending end portion of fluid-tight conduit member 48 of folding link conduit means 19. Pivoting bracket 107 is pivotally connected to second yoke member 102 by pin element 108. Fluid-tight conduit member 48 is provided with two square-shaped conduits 109 and 111 having there ends sealed by any suitable means such as plate member 112 welded thereto. Square-shaped conduits 109 and 111 are provided with connectors 113 and 114 which are in fluid communication with the interior of square-shaped conduits 109 and 111, respectively. Connectors 113 and 114 are in turn connected to hose members 57 and 58 which are connected then to hydraulic cylinder 41 of second wheel means 22.

Referring now to FIG. 4, a front plan view of hinge means for a twenty four and/or thirty two foot in length sectional support beam is shown. As can readily be seen second yoke member 102 is positioned at about a ten degree angle with respect to the vertical plane of first yoke member 97. The angle formed between first yoke member 97 and second yoke member 102 is critical depending upon the length of the sectional support beam 18 of foldable frame structure 11 so that folding link conduit means 19 and 21 can be caused to rise up and over the upper surface of A-shaped frame means 13 and, at the same time, after passing over A-shaped frame means 13 drop the desired distance to allow folding link conduit means 19 and 21 to be positioned within lock means 31 Without the aid of guiding structures. Further, folding link means 19 and 21 are supported by elongated members 26 and 27 of A-shaped frame means 13 when in a folded position.

Referring now to FIG. 5, a front plan view of a hinge for a forty foot in length sectional support beam is shown. As can readily be seen, second yoke member 102 is positioned at about a seven degree angle with respect to the vertical plane of first yoke member 97. Again, it should be stressed that the angle between the first yoke member 97 and the second yoke member 102 is critical depending upon the length of sectional support beam of the foldable frame structure so that the folding link conduit means can be caused to rise over the upper surface of the frame structure and, at the same time, allow the folding link conduit means to drop the desired distance to be positioned within the lock means without the aid of guiding means structures. Further, the hinge allows the folding link conduit means to drop a sufficient distance thus the folding link conduit means are supported by A-shaped frame structure thus reducing the strain on folding link conduit member and providing a more durable, desirable, and inexpensive means for maintaining the foldable frame structure in a relatively fixed position without the need of auxiliary structures and guiding means.

The foregoing discussion and description has been made in connection with preferred specific embodiments of the hinge mounting means for frame structures for longitudinal relative movement of the invention. It is to be understood that the foregoing discussion and description is only intended to illustrate and teach those skilled in the art how to practice the invention.

We claim:

1. In a foldable frame means having a folding link means and wherein said foldable frame means has a. frame structure and -a sectional support beam having a central section and opposed end sections pivotally connected thereto and said central section is connected to said frame structure and transversely extends therefrom, a hinge for longitudinal relative movement of said folding link means, comprising:

(a) a bracket means mounted on each of said opposed end sections of said sectional support means;

(b) a hinge means pivotally connected to said bracket means and rotatable about a substantially horizontal axis through said bracket means, said hinge means having an inclined axis relative to the substantially horizontal axis through said bracket means and spaced therefrom and with the amount of angle of incline relative the length of said support beam; and

(c) a coupling means mounted on one end of said folding link means and pivotally connected to said inclined axis of said hinge means, said bracket and hinge means constructed and cooperatively connected as above stated so that upon said frame means being folded said folding link means rises up and over said frame structure.

2. The hinge according to claim 1 wherein said bracket means comprises two plate members mounted on each of said opposed end sections of said sectional support bean, said plate members being maintained in a spaced relationship and having axially aligned openings therein adapted to having a pin element positioned therein.

3. The hinge according to claim 1 wherein said hinge means comprises:

(a) a first yoke member having two parallel leg members maintained in a spaced relationship with each other by a base member connected to one end of each of said parallel leg members, said parallel leg members being provided with axially aligned openings adapted to have a pin element positioned therein at their end portion furtherest removed from said base portion; and

(b) a second yoke member having two parallel leg members maintained in a spaced relationship with each other by a base member connected to one end of each of said parallel leg members, said parallel leg members being provided with axially aligned openings adapted to have a pin element positioned therein at their end portions furtherest removed from said base member, said base member of said second yoke member being connected to the base member of said first yoke member so that the aligned openings in the leg members of said second yoke member are provided with an inclined axis relative to the horizontal axis of the aligned openings in the leg members of the first yoke member and with the amount of angle of incline inversely variable with respect to said support beam.

4. The hinge according to claim 3, wherein said inclined axis of said second yoke member relative to the horizontal axis of said first yoke member is in the range of about five to eleven degrees.

5. The hinge according to claim 3, wherein said inclined axis of said second 'yoke member relative to the horizontal axis of said first yoke member in the range of about seven to ten degrees.

6. The hinge according to claim 5 wherein the inclined axis of said second yoke member relative to the horizontal axis of said first yoke member is about seven degrees and wherein the length of the sectional support beam is Within the range of about 24 to 34 feet in length.

7. The hinge according to claim 5 wherein said inclined axis of said second yoke member relative to the horizontal axis of said first yoke member is about ten degrees and the length of the sectional support beam is about 40 feet in length.

8. A hinge for longitudinal relative movement accordin to claim 1 wherein:

(a) said bracket means comprises two plate members mounted on each of said opposed end sections of said sectional support beam, said plate members being maintained in a square relationship and having axially aligned openings therein;

(b) said hinge means comprises a first yoke member having two parallel leg members maintained in a spaced relationship with each other by a base member connected to one end of each of said parallel leg members, said parallel leg members being provided with axially aligned opening adapted to have a pin element positioned therein at their end portions furthest removed from said base portion and a sec ond yoke member having two parallel leg members maintained in a spaced relationship with each other by a base member connectetd to one end of each of said parallel leg members, said parallel leg members being provided with axially aligned openings adapted to have a pin element positioned therein at their end portions furtherest removed from said base member, said base member of said second yoke member being connected to the base member of said first yoke member so that the aligned openings in the leg members of said second yoke member are provided with an inclined axis in the range of about seven to ten degrees to the horizontal axis of the aligned openings in the leg members of the first yoke member; and

(c) said coupling means comprises two plate elements mounted on the rearwardly extending end portion of said folding link means and maintained in a parallel spaced relationship with each other, said plate elements having axially aligned openings in their end portion removed from said folding link means.

References Cited UNITED STATES PATENTS 2,658,770 11/1953 Koenig 280412 2,828,597 4/1958 Moore 172456 X 3,190,367 6/1965 Kopaska 172456 3,411,467 11/1968 Van Der Lely 111-86 X LEO FRIAGLIA, Primary Examiner US. Cl. 172 .456 

